The tuna season came to close before I had a chance to test this in the wild, but I did test it out on the boat. Unfortunately, my micro SD card decided to take a dump and I lost all my footage. I'm in the process of recovering it. Really sucks.
Here is the only clip that survived. It was a quiet day, no monster tuna around.
In the next iteration of this project, I think the mackerel will be put in a holder or tube of some kind. I mean, poor little fish... The dangling is not so nice. But then again, neither is fishing for large tuna.